The Beginner’s Guide to a Low FODMAP Diet

Do you often experience digestive stress after eating certain foods?

Can the discomfort be so severe that it affects your day-to-day activities?

The link between foods and digestive disorders is well recognized, and there is a good chance that FODMAPs – small carbohydrates in certain foods – are the culprit.

As a clinical dietitian, I’ve seen how remarkable a low-FODMAP diet can be for people with chronic gastrointestinal symptoms… things like recurrent bloating, gas, cramps, diarrhea or constipation. There’s also many new case studies suggesting it can help with several other chronic health conditions too.

If you’re keen to learn more, and maybe even try a low FODMAP diet for yourself, this beginner’s guide is a great place to start.

What You’ll Learn:

  • What is FODMAPs and who should be concerned
  • Common FODMAPs listed on food labels, and where gluten fits into the picture
  • The best studies behind a low FODMAP diet
  • An all inclusive low FODMAP shopping list
  • Probiotics and their role in the diet
  • A sample low FODMAP diet plan and ideas when dining out.

What is low FODMAP and who is it for?

guts intestines stomachA low FODMAP diet refers to a temporary eating pattern that has a very low amount of food compounds called FODMAPs.

The acronym (as described by co-creator Sue Shepard) stands for:

  • Fermentable – meaning they are broken down (fermented) by bacteria in the large bowel
  • Oligosaccharides – “oligo” means “few” and “saccharide” means “sugar.” These molecules are made up of individual sugars joined together in a chain
  • Disaccharides – “di” means two. This is a double sugar molecule
  • Monosaccharides – “mono” means single. This is a single sugar molecule
  • And Polyols – these are sugar alcohols (however, they don’t lead to intoxication!)

Let’s stick with the term FODMAPs shall we?

Those saccharides and polyols are short-chain carbohydrates that, if poorly digested, ferment in the lower part of your large intestine (bowel). This fermentation process draws in water and produces carbon dioxide, hydrogen and/or methane gas that causes the intestine to stretch and expand.

The result is strong pain, bloating, visible abdominal distension and other related symptoms (1).

FODMAPSImage source.

Who is a low FODMAP diet for?

Its primary use is to relieve digestion-related symptoms, but is emerging as a useful treatment tool for several other conditions too. It can be useful for those with:

  • Irritable Bowel Syndrome (IBS)—more on that below
  • Other forms of Functional Gastrointestinal Disorder (FGID)
  • Small intestinal bacterial overgrowth (SIBO)
  • Certain auto-immune conditions/diseases like (potentially) rheumatoid arthritis, multiple sclerosis or eczema
  • Fibromyalgia or other health issues you’ve noticed are triggered by certain foods
  • Frequent migraines that appear to be triggered after certain meals
  • May help those with a histamine intolerance

The best candidates for trialing a low FODMAP diet also tend to answer yes to these questions.

Summary: FODMAPS are short-chain carbohydrates that, if poorly digested, ferment in the bowel to cause severe digestive stress. A low FODMAP diet is designed to temporarily restrict the amount of FODMAPs consumed and is useful for treating conditions like IBS.

Common FODMAPS and what to look for on the label

magnifying glassCommon FODMAPs in your food include:

  • Fructose: A sugar found in most fruits and vegetables.
  • Lactose: A sugar found in dairy foods like milk.
  • Fructans: Very similar to fructose, found in many vegetables and grains
  • Galactans: Found primarily in legumes.
  • Polyols: Sugar alcohols like xylitol, sorbitol, maltitol and mannitol. You find them mainly in artificial sweeteners and chewing gum.

Best practice is to read the ingredients label for other added FODMAP ingredients such as inulin (chicory root), natural flavors, high fructose corn syrup, agave, honey, etc.

What about gluten?

While gluten can also trigger food sensitivities in a handful of people, it is a protein, not a carbohydrate.

Therefore gluten cannot be classified as a FODMAP.

However, gluten-free products do still appear beneficial for those with FODMAP sensitivities. Testing from Australia’s Monash University shows that gluten-free products almost always have reduced amounts of fructans and oligosaccharides.

That means gluten-free products are generally lower in FODMAPs, and free of gluten of course.

Summary: FODMAPs exist mainly in dairy, legumes and many fruits and vegetables. While gluten is not technically a FODMAP, gluten-free products are typically lower in FODMAPs anyway.

A low FODMAP diet is very restrictive and designed to be temporary

Stop eating bananaBefore we go any further, it’s important to clarify that following a low FODMAP diet is very restrictive and cuts out numerous common foods and food groups.

That means you need to reintroduce  foods at some stage, so it cannot be a permanent solution.

The idea is that restricting all FODMAPs at once should have a far greater and more consistent effect than simply restricting one FODMAP in isolation. With all FODMAPs out of your diet, it gives your gut bacteria a chance to correct any imbalances, and your gut some time to heal.

How it works

For 3-8 weeks (depends on how you respond) you strictly limit or exclude all FODMAPs from your diet. This is known as the elimination phase.

A period shorter than 3 weeks can occasionally be used if you’ve undergone hydrogen breath testing to identify which specific FODMAPs are the most problematic. But otherwise it’s likely you will require at least 3 weeks for the body to adjust and ‘reset’.

After this time you then begin the reintroduction phase—reintroducing each FODMAP type one at a time to see what triggers symptoms. For example, you may first reintroduce fructose (a type of sugar) for one week. If you have no symptoms, you may then reintroduce lactose too, and so on.

Once the trigger FODMAPs have been identified, you will know what you can and cannot eat. So it’s basically a specialized form of elimination or exclusion diet.

Summary: A low FODMAP diet is not designed to be permanent. It is highly restrictive for several weeks, before foods are slowly reintroduced to determine what causes symptoms.

IBS and studies that support a low FODMAP diet

test tubeMuch of the research has been on patients with Irritable Bowel Syndrome (IBS).

IBS is a chronic gastrointestinal disorder characterised by abdominal pain and altered bowel habits, and around two thirds of IBS patients report their symptoms are related to food. It’s now estimated to affect 11% of the population globally, up to 13% in Australia and up to a whopping 20% in the US and UK (2, 3).

The highest quality evidence to date was a 2014 Australian clinical trial that compared the effects of a low FODMAP diet between 30 IBS patients and 8 similar individuals without IBS (to act as a control group for comparison).

Participants were randomly assigned to receive either a diet low in FODMAPs (less than 3 grams per day) or a typical Australian diet for 21 days. This was followed by a long “washout period,” before crossing over to the alternate diet for another 21 days. Almost all food was provided to the participants, and breath hydrogen and stool samples were collected frequently (4).

This is what happened:

fodmap studyImage source.

IBS symptoms were reduced by 50% overall on the low FODMAP diet, with the greatest improvements observed one week after implementing the diet. More specifically, improvements were seen for bloating, abdominal pain, wind and dissatisfaction with stool consistency.

Numerous similar studies (albeit not as well designed) have found very similar benefits, and the overall average success rate is about 68-76% of patients (5, 6).

Research in this area still has a way to go, but scientific consensus is that a low FODMAP diet should be the first dietary approach for treatment of recurrent gastro-intestinal issues.

Summary: Controlled trials continue to find that a well-designed and supervised low FODMAP diet improves symptoms by about 50% in as little as one week. The average success rate is 68-75% of patients that try it.

The essential low FODMAP food list for shopping

The following is a list of foods that are low in FODMAPs.

It’s arguably the most complete free list available as I compiled the best of other great list sources including the Journal of Gastroenterology and Hepatology, and Kate Scarlata. I recommend you save this to use as a shopping guide, alongside the Monash University FODMAPs app (does cost money, but worth it).

There are some important notes below the list you should read too.

LOW FODMAPs SHOPPING LIST  finalMany legumes not included on this list (such as kidney beans and split peas) can be made far more digestible and low FODMAP by pre-soaking for 7-24 hours.

Also note that like with anything food related, portion size is fundamental. A serving of almonds are considered low FODMAP, but if you eat an entire bowl of almonds then you will end up eating a high amount of FODMAPs.

As with anything we eat, the dose makes the poison.

Summary: Above is an essential list of low FODMAP foods that you can take with you when grocery shopping. Remember that many of these foods still contain trace amounts, so portion size is fundamental.

 

Probiotics may help ease symptoms

Preserved  autumn vegetables on shelf near a wooden wallRecent data suggests there is a strong link between the balance of our gut bacteria (its composition) and health. An imbalance of this bacterial “community” – known medically as gut dysbiosis – can cause many problems… especially gut issues.

Probiotics is the term used to describe the bacteria we eat specifically for to restore this balance and improve health. Additional probiotics in the diet has been shown to improve a range of health aspects from gut health to weight loss.

So how does this relate to FODMAPs?

Well it’s thought that fermentation of FODMAPs directly upsets the bacterial balance in our gut. In fact, growing evidence shows that many subgroups of IBS patients have a highly irregular gut bacterial environment (7).

The question posed now is will the addition of “good” bacteria – from probiotics – help to manage FODMAP sensitivities? The research is promising.

A 6-week Danish study randomly assigned 123 IBS patients to either a low FODMAP diet, a regular Danish diet supplemented with two daily doses of Lactobacillus (probiotic), or just a regular Danish diet. Results found that both the intervention diets led to clinically significant improvements in symptom severity, although low FODMAPS was still best (8).

 

probiotic for fodmapChanges in self-reported symptom severity can be seen in the low FODMAP diet group (figure A) and the Lactobacillus group (figure B) from the study’s start point until week 6. These data suggest that probiotic supplementation may be a useful treatment tool, although the mechanism is still not understood.

The question that comes to my mind is: What about probiotics alongside a low FODMAP diet?

This hasn’t been studied yet, but I suspect it could be very beneficial, especially considering that probiotic supplementation does not typically have side-effects. There might be a week or so of unpleasantness, but the ability to tolerate a wider variety of foods in the long-run is well worth that initial discomfort.

You could start by trialing some probiotic rich foods like quark, kefir yogurt and pickled vegetables such as sauerkraut. However the potential problem here is that fermented foods are rich in a food chemical called histamine, which some people may also be sensitive to. This fact should be considered on an individual basis (9).

Probiotic supplementation is another popular alternative to consider, and this is what was used in the studies.

Summary: Poorly absorbed FODMAPs are thought to directly upset the bacterial balance in our gut. In line with this theory, regular probiotic supplementation has been shown to effectively reduce symptom severity in IBS patients. I suspect that the addition of probiotics to a low FODMAP diet will be very beneficial.

A low FODMAP diet plan and dining out ideas

close up of diet plan and food on tableDiet plans are generally tailored to individual patients as we all have different eating habits and preferences.

However I have put together a sample 14-day low FODMAP diet plan that you can see here.

There are also pre-packaged foods formulated to be low in FODMAPs if you prefer the convenience. You will need to ask about these in your local store.

Low FODMAP dining out ideas

Set meal plans aren’t particularly useful when you’re eating out at a restaurant or takeaway shop. Here are some food choice tips to help you make appropriate choices:

  • Ask for gluten-free bread (preferably white)
  • Breads or cereals made from oats for breakfast
  • Coffee or tea with lactose-free milk
  • Lactose-free yogurt served with low FODMAP fruits (Greek yogurt is okay too but still has some FODMAPs)
  • Smoothies made with lactose-free milk and low FODMAP fruits and vegetables
  • Low FODMAP salad with nuts, seeds, extra virgin olive oil & fresh squeezed lemon
  • Roasted, steamed or grilled low FODMAP vegetables
  • Choose meat, fish, egg or tofu dishes that are plain (separate from sauces/gravies)
  • Chicken with egg mayonnaise or beef with mustard
  • Small French fries is okay at fast-food restaurant (although not encouraged obviously)
  • Carrot and cucumber sticks with hummus as starter or snack
  • Beef nachos on corn chips
  • Curry dishes with rice is generally okay, but it depends on the curry paste used.
  • Popcorn at the cinema
  • Sushi and sashimi with soy sauce and wasabi
  • Fill a thermos with lactose-free milk or almond milk to add to oats/oatmeal when traveling.

Summary: At the beginning of a low FODMAP diet it’s much easier if you prepare your own meals at home, just to get familiar. And while it can seem overwhelming at first, trends start to emerge between what you can eat at home and dining out.

DIY or do I need help from a Dietitian?

As you can see the low FODMAP diet is complex.

This is generalized advice and may be difficult to do yourself without professional guidance.

In fact, it has only ever been evaluated formally as a dietitian-delivered diet. Group education sessions have recently been used with success, but it’s traditionally done in a one-on-one setting so that any diet modifications are individualized.

That said, with the quality of resources now available online it certainly can be done on your own, but you must be highly motivated. I strongly recommend you follow dietitians Kate Scarlata and Patsy Catsos for useful guides.

Safely removing and reintroducing the appropriate foods takes a lot of learning upfront, but countless satisfied patients can tell you it’s worth it.

This post was originally published on Diet vs Disease.

106 comments

Tanya W
Tanya W4 months ago

Thank you

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Tanya W
Tanya W4 months ago

Comprehensive article 🍌

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Peggy B
Peggy B4 months ago

Noted

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Elena Poensgen
Elena Poensgen4 months ago

Thank you

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Elena Poensgen
Elena Poensgen4 months ago

Thank you

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Karin Geens
Karin Geens4 months ago

Thanks , very interesting

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Marija M
Marija M4 months ago

tks

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Naomi D
Naomi Dreyer4 months ago

WOW! Lots of info. I have to read this again. Maybe more than once.

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Camilla V
Camilla Vaga5 months ago

noted

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Lisa M
Lisa M5 months ago

Noted.

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